Catheters used in medical and other fields, such as vascular catheters or urethral catheters for urethral catheterization, are inserted into blood vessels, digestive tracts, tracheae, bile ducts, or ureters and used in aqueous solutions like blood or body fluids. Therefore, they need to be able to be smoothly inserted without damaging tissues.
In order to satisfy this requirement, a low friction lubricant is applied to the surface of a catheter, or the surface of a catheter is coated with a lubricant layer before use (see Patent Literatures 1 to 3). However, unfortunately, these applied or coated lubricant layers have insufficient lubricity and, further, their lubricity is reduced due to e.g. their separation or peeling during movement within a vessel or a tract because these layers are not chemically fixed to the catheter surface.